The present invention relates to polyurethanes containing certain (meth)acryloyl groups (as used herein, the term "(meth)acryloyl" means acryloyl or methacryloyl) which can be converted by radiation curing into crosslinked products, even in the presence of atmospheric oxygen, using peroxides or hydroperoxides, to a process for their production. The products herein may be used as binders for coating or surfacing compounds and for the production of moldings.
Polyurethanes containing (meth)acryloyl groups which are obtained as a reaction product of polyisocyanates and hydroxyalkyl acrylations or methacrylates, as described for example in German Offenlegungsschriften 1,644,798, 2,115,373 or 2,737,406, are known They are cured by high-energy radiation, such as UV light or electron beams, and are used for coating, for example wood, or for the production of coatings for graphic purposes.
German Offenlegungsschrift 3,737,244 describes polyurethanes containing (meth)acryloyl groups which can be crosslinked not only by radiation, but also by peroxides. However, this advantage is acquired at the expense of using special isocyanurate polyisocyanates prepared in a separate step as starting material for the production of the polyurethanes.
The problem addressed by the present invention was to provide polyurethanes containing (meth)acryloyl groups based on simple, inexpensive aliphatic diisocyanates which could be cured not only by radiation, but also using peroxides in the presence of atmospheric oxygen and which, at the same time, would be at least equivalent to the known systems in regard to the viscosity and technical properties of the resulting products.